鸡胚心肌细胞膜上外向钾电流的特征(英文)  

Characterization of outward potassium current in embryonic chick heart cells

作　　者：梅岩艾[1] 黄洛秀[1] 魏华[1] 孙家庭[1] 周汉清[1] 张志鸿[1] 

机构地区：[1]复旦大学生理学和生物物理学系立人实验室

出　　处：《中国药理学报》1999年第4期303-307,共5页Acta Pharmacologica Sinica

基　　金：Project supported by the National Natural Science Foundation of China (№ 39730150)

摘　　要：目的:研究原代培养黄羽鸡胚心肌细胞上存在的外向钾电流特性,方法:膜片箝技术的“全细胞”记录,结果:此细胞模型上的钾电流动力学和药理学特征均不同于白羽鸡胚心肌细胞上的报道,钙通道阻断剂镉离子可消除此电流,异丙肾上腺素和cAMP通过磷酸化增加电流的峰值和缩短达到最大峰电流的时间,通道被磷酸化修饰后出现频率依赖性负性效应,结论:黄羽鸡胚心肌细胞上存在着钙激活的钾通道,磷酸化修饰不仅改变其开放速率还延长通道失活后再复活的时间,此结果也说明,同一种动物其细胞膜上离子通道的特性可因不同种系而各异。AIM: To characterize a voltage-dependent outward K+ current in cultured heart cells of 14 - 16-day-old embryos of yellow chick. METHODS: The patch-clamp technique in the whole-cell configuration was used. RESULTS: The kinetics and the pharmacology of the outward K+ current in our cell mold were different from those described in white chick. Like the calcium-activated K+ current, blocker of calcium channel, CdCl2, eliminated the current of more than 95 % . Isoproterenol provoked an increase of peak amplitude (137 %± 47 %, n = 16 cells) and acceleration of activation kinetics in the outward K+ current (the time reaching a peak current reduced from 36 ms ±10 ms to 16 ms± 9 ms) . This effect of isopro-terenol was mimiced by cAMP. In addition, a frequency-dependent decrease in peak amplitude of the current occurred after cAMP-induced phosphorylation. CONCLUSION: There are species- and/or cell-type-specific difference in the K+ channels properties. In embryonic yellow chick heart cells, the phospholation of channel could not only modulate the activation kinetic properties of the calcium-activated potassium channel, but also change their recovery kinetics.

关 键 词：鸡胚 钾通道 心肌细胞膜 磷酸化 钙拮抗剂 

分 类 号：R972[医药卫生—药品] Q25[医药卫生—药学]